Preparation of vitamin concentrate



Patented July 9, 1940 2,207,385 PREPARATION OF VITAMIN CONCENTRATEGerald G. R. Smith, Rochester, N. Y., assignor. by mesne assignments, toDistillation Products, 1110., Rochester, N. Y a corporation of DelawareNo Drawing. Application September 21, 1936, Serial No. 101,778

6 Claims; (01. 202-57) This invention relates to an improved process ofobtaining fat soluble vitamin concentrates from natural oils, such asmarine animal oils.

In subjecting marine animal oils, such as cod- -process whereby afraction containing vitamins A- and D in the high boiling form, obtainedas a mixture by. the high vacuum distillation of marine animal oils, canbe segregated into its individual liver oil, to molecular distillation,it has been vitamin components and the vitamins simultane- 6 found thatvitamins A and D are present in two ously concentrated. A still furtherobject is to different forms which distill in substantially dif- DrOVidea Process whereby a high vacuum distilferent temperature ranges. It hasbeen shown late of a marine animal oil, which distillate conin theco-pending application #67332, filed tains the high boiling form ofvitamin D and sub- 10 March 5, 1936, in the name of K. C. D. Hickman,stantial amounts of glycerides, can be substan- 10 that substances haveno fixed boiling point under tially concentrated and a vitamin D conmolecular conditions, but distill at different rates m terial of highpotency obtained. Other obaccording to the temperature. The relativeboiliects will appear hereinafter. ling points are best described inrelation to those e e je s a e accomplished by saponlfyi of certainsubstances chosen as standards. Thus a high Vacuum stillate Containingvitamins A 15 the low boiling form of vitamin A is obtained in and/or Din the h boiling e ad ing a 501- maximum amounts at a temperature ofabout vent for the non-saponifiable vitamin fraction, under conditionswhere celanthrene Red which solvent has a substantially differentboiling 3B distills at 124 C. The low boiling form of point undermolecular conditions than the vitavitamin D is obtained at about 160C.-,on the n and subjecting the solvent-vitamin mixture 20 same scale.The high boiling form of vitamin A, to high vacuum distillation toseparate the vitawhich has been found to be composed of vitamin minstherefrom.

A alcohol esters, distills at a temperature between In the followingexamples and description, I abou 180 and 235 C. A high boiling form ofvithave described several of the preferred embodiamin' g'l) distills inmaximum amounts at about ments of my invention but it is to beunderstood 25 194 6., but is obtained in lesser amounts at temthat theyare set forth for purposes of illustration peratures between 180 and 260G. Since the and not as limitations thereof. high boiling forms ofvitamins A and D distill The high boiling fraction containing eithervitover substantially the same range, they are obamin A or D alone, 1' amixture f the W is tained as a mixture, unless relatively narrow cuts uj cted to sap fi in Order to destroy 30 are taken. Even if suchprocedure is followed, it e g y e des which would otherwise contaminateis difiicult to separate fractions which contain all t e V mins 0nredistillation. It would seem that of the high boiling A and all of thehigh boiling since the non-saponifiable fraction was insoluble D withoutadmixture of one with the other. Such it Could e separated Without asolvent In D acmixtures can be redistilled and substantially sege,wever, it has such small bulk and is so 35 reg'a'ted, but since eachdistillation results in at thoroughly entrained With e soapy emulsionleast partial decomposition, such procedure is not that centrifugingprolonged standing is necesdesirable. A further diificulty is that thedistillay to Cause t e sep tion, which is then intion temperatures ofthese vitamins is so high Complete Since the Vitamin active components40 that a considerable amount of the oil or glyceride are present as anonsaponifiable porti they 40 itself distills, thus causing asubstantial dilution can be dissolved in a s ve t having a different ofthe vitamin distillates. Many such fractions distilling P t from that ofthe vitamin constituare too weak t be of commercial ot ents and themixture of solvent and vitamins thus especially if narrow cuts aretaken, are entirely Obtained an be subjected to high vacuum dissuitablefor therapeutic use, but are not suflicienttillation and the vitaminsseparated as individual 45 1y potent for various particular purposes.Redis fractions with ease. The saponification treattillation of suchmaterial, as pointed out above, is ment is preferably complete, but ifit is desired to not at present feasible. obtain a concentrate ofpredetermined potency or This invention has for its object to overcometo have part of the original oil distill and be presthe abovedeficiencies of high vacuum distillation ent with the vitamindistillate, it is possible to 50 of fat soluble vitamin containingnatural oils. saponify only part of the glycerides, the non- Anotherobject is to provide a process whereby saponified portion beingseparated as an upper high Vacuum distillates containing high boilinglayer with the vitamins and this material can be forms of vitamins Aand/or D can be substantially separated and directly distilled ordissolved in a concentrated. Another object is to provide a solvent anddistilled as described above. 55

iiication the unsaponified portion of the oil acts in the place of, oras a solvent. Where at least a third of the oil is saponifled nearly allof the triglyceride molecules are altered. Mono and diglycerides areproduced and some of these polymerize to form poly-glyceride fatty acidcomplexes. On distillation, therefore, some of the oil distills attemperatures lower than the vitamin and some at temperatures muchhigher. The middle portion containing substantially all the vitamincomes over in purified and concentrated condition.

The saponificatlon treatment is carried out in the same manner that hasbecome conventional in the vitamin art. Such procedure is preferablycarried out in an inert atmosphere in order to avoid oxidation of potentconstituents. Any alkali such as caustic potash, caustic soda, or theusual equivalents, such as lime, ammonia, etc., may be used as asaponifylng agent. It is sometimes desirable to add a small amount ofalcohol, such as ethyl or methyl alcohol, to assist rapid saponificationwith the minimum application of heat or without external heating at all.The saponifying agents are preferably employed as strong solutions,although solids are entirely satisfactory and are usually necessary withalkalies of low solubility, such as lime. If water is used during thesaponification treatment, the non-saponifled material separates out asan upper layer and soaps remain dissolved in the aqueous portion. Whenno water is used, or relatively small amounts of water, it is desirableto dilute the saponiflcation mixture with water before adding thesolvent. This procedure, in fact, is usually desirable regardless of thesaponification treatment used. Since the soaps obtained vary in degreeof solubility, depending on the type of base used, it is desirable toemploy a base which gives a soap which is readily soluble in water.

After saponification is completed, hot water is added and a portion ofsolvent or extracting oil is added.. The materials are agitated andallowed to settle. If emulsions are formed the usual expedient foremulsion breaking, such as heating, may be used. Such emulsions seldomform in the initial extractions, but may do so in the followingapplications of solvent. After the mixture has settled, the topsolvent-vitamin layer is withdrawn and another portion of solvent may beadded in order to complete the removal of the vitamins. The number ofsolvent extractions varies according to the mount of solvent used, withthe period of mixing, with the temperature andwith the type ofdistillate treated and the amount of vitamin present therein. Theprocedure cannot, therefore, be limited to specific proportion but iscarried out in well known manner using conventional solvent extractionmethods. After the vitamins have been completely dissolved in thesolvent, the different solvent extracts are combined and either washedwith water to remove residual soaps or acidified to convert the soapsinto fatty acids and then washed to remove residual acidifying acid andsalts. The material is then dried and preferably degassed and thenconveyed to a high vacuum still where the vitamin constitutent isrecovered.

In selecting a solvent for the extraction of the solvents from thesaponifled oil, it is necessary to use a solvent which has asubstantially diflerent boiling point or distilling temperature than thevitamin constituents. It is, of course, also necessary to use a solventwhich has a good ing forms of vitamin A when employing the expedient fpartial saponsolvent power for the vitamins.

Glycerides of various types can be used and I have found that a mostsuitable solvent is one which is obtained as .a residue from themolecular distillation of whole marine animal oils. The materialconsists almost entirely of fatty glycerides having very low vaporpressures and it distills at such a high temperature that the vitamincan be distilled oil carrying very little diluent oil with it. Ifdesired, such a low vapor pressure solvent can be mixed with a smallamount of higher vapor pressure solvent, such as a higher vapor pressurefish oil fraction, which minor portion will distill with the vitamins,thus giving a distillate having a larger volume and, if desired, apredetermined degree of potency. Instead of using the distillationresidue, a whole fish oil or any other suitable solvent such asphthalate esters etc. having a suitable vapor pressure can be used.

As explained above, the distillate initially treated is one containingeither of the high boilor D, or both. It may be a fraction whichcontains any proportion of the vitamin and the glyceride. Since both ofthese high boiling forms can be substantially concentrated on the firstdistillation of the fish oil, it is desirable to segregate as much ofthe potent materials as possible on the first distillation and tocollect the remaining materials as a broad cut containing considerableamounts of the oil and treat this according to my invention. Byoperating in this manner, a substantial proportion of the high boilingforms is recovered as a concentrate of high potency by one distillationtreatment and it is, theferore, unnecessary to further concentrate themor subject them to the redistillation and saponification treatmentoutlined above. Thus, on distilling the initial fish oil the highboiling forms of vitamins A and D distill in maximum amounts at about190-200" 0., compared with Quinizarine green at 220 C. This fraction isseparated and is ready for immediate therapeutic use without furthertreatment unless dilution with an inert oil is necessary to bring itdown to a potency suitable for administration. Fractions from 150-190and 20(L-260 can be separated and treated according to the hereindescribed invention. It is to be understood that this constitutes mypreferred mode of operation and that my invention is not to be limitedto such procedure, since it is possible and, in many cases, desirable toseparate the fractions in a different manner and treat particularfractions, or to separate the entire high boiling vitamins as onefraction and then treat the whole material.

The following example illustrates one specific mode of carying out myinvention:

88.5 grams of a cod liver oil molecular distillation fraction distillingat 190-250 saponified with 30 grams caustic potash dissolved in cc. ofwater, an addition of 50 cc. of ethyl alcohol being made to assist theprocess.

450 cc. of hot water at about 80 C. were added. Four separateextractions or washings were given, using the residual oil from a codliver oil distillation as the extraction material. The quantities usedwere:

' Cubic centimeters 1st extracti n 600 2nd extracti n 300 3rd extraction300 4th extraction 200 The collected oil portions of the aboveseparation were then treated with excess dilute acetic C. were acid andfollowed by separation and successive water washings till the wash waterno longer high potency at 170 C.

It is to be understood that many variations and changes can be made inthe above described procedure without departing from the spirit andscope of my invention. For instance, it is possible to employ a solventwhich has a lower distillation point under molecular conditions than thevitamin and distill off the solvent leaving the vitamin as a residue, oralso distill off the vitamin as a separate fraction. Such procedure isnot as advantageous, however, since no material is left to dilute thevitamin and decomposition on the heating surface is thereby increased.All operations are preferably carried out under non-oxidizing conditionsand can conveniently be carried out in the presence of an inertatmosphere. All saponiflcation, washing and solvent extraction procedureis carried out in the manner conventional in the vitamin and chemicalart and can be varied greatly within the scope of my invention.

The final high vacuum treatment is preferably carried out undermolecular distillation conditions. This type of distillation involvesthe use of such a low pressure. that the distilling molecules have anappreciable mean free path and are condensed on a surface located at adistance from the evaporated surface of less than about the mean freepath of the molecules of residual gas. Pressures below .1 of amillimeter and preferably below .01 of a millimeter, such as .005 to.0001 millimeters, are used. Distances separating the evaporative andcondensing surfaces are usually less than about 12" such as, forinstance to 6 inches. Since the mean free path is inversely proportionalto the pressure, there is no limit to the distance which can be used orlower limit to the pressure but, due to the difiiculty of producing andmaintaining extremely low pressures, I have found it most economical tooperate under conditions set forth above. It has been found thatvitamins can be distilled under conditions which do not involvemolecular distillation. In such case, the surfaces are separated by adistance many times the mean free path and the distilling moleculestravel from the evaporative to the condensing surfaces by diffusionand/or convection. Such procedure can be used in my process and ,is tobe understood as being within that type of distillation known as highvacuum short path distillation. One aspect of such nonmolecular highvacuum distillation is disclosed in the copending application to K. C.D. Hickman No. 99,632, filed Sept. 5, 1936.

The fractions treated in accordance with my process can be obtained byany type of high vacuum distillation of any marine animal oil containingfat soluble vitamins such as cod-liver, halibut, liver, tuna, salmon,and other fish oils. They are preferably produced by a short path highvacuum or molecular distillation process of the nature of that describedin the Hickman Patent 1,925,559 or by the process of the nature of thatdescribed in the above referred to Hickman application.

It has been definitely established that the high boiling form of vitaminA contained in the dis tillates treated in the above-described processis an ester. The saponiflcation treatment converts the ester intovitamin A alcohol which distills at about 118 or at the same temperaturethat the low boiling form of vitamin A is obtained. It is not known whatthe constitution of the high boiling form of vitamin D is, but thesaponiflcation treatment converts it into a low boiling form whichdistills at a temperature approximating that of the low boiling form ofvitamin D. This conversion product appears to have the sameanti-rachitic potency that the low boiling form has. My invention,therefore, has the distinct advantage that the oil is not only removedand concentration made easier, but also that the vitamins can be,distilled at a substantially lower temperature and destruction duringdistillation considerably reduced. Since the vitamins are converted intothese lower boiling forms by the saponiflcation treatment the solvent isselected upon the basis of its vapor pressure relation to thesecompounds. In other words the solvent selected should have a difierentdistillation pointfrom that of the vitamin constituent in its convertedor low boiling form.

What 1 claim is:

1. The process which comprises subjecting ,a molecular distillate ofcod-liver oil having a molecular distillation range of between about 180and 260 C. and containing the high boiling form of vitamin D tosaponiflcation, adding a glyceride consisting of a moleculardistillation residue of a fish oil, to the saponiflcation mixture,separating the mixture of non-saponifiable matter and glyceride andsubjecting it to molecular distillation and recovering the vitamins inthe distillate.

2. The process which comprises subjecting a molecular distillate of afish oil having a molecular distillation range of between 180 C. and 260C. and containing the high boiling form of vitamin A or D tosaponiflcation, adding a vitamin solvent which has a lower vaporpressure than the vitamin constituents, separating the vitaminsolventmixture, subjecting it to molecular distillation and separating afraction containing a vitamin.

3. The process which comprises in combination, subjecting a vitamincontaining marine animal oil to high vacuum distillation, separating afraction which contains the high boiling form of vitamin D, subjectingthis fraction to a saponifi-.

cation treatment, separating the non-saponified portion by dissolving ina solvent having a different boiling point than the vitamin andsubjecting it to high vacuum distillation to recover the vitamin contentthereof.

4. The process which comprises in combination, subjecting a vitamincontaining fish oil to high vacuum, short path distillation, separatinga fraction which contains the high boiling form of vitamin D,saponifying this fraction, dissolving the non-saponifiable portion in asolvent for the vitamin contained therein, which solvent has a differentdistillation temperature from the vitamin, subjecting thesolvent-vitamin mixture to high vacuum, short path distillation andseparating the vitamin as a distillate.

5. The process which comprises in combination, subjecting a vitamincontaining fish oil to short path distillation at a pressure of lessthan about .1 mm. separating a fraction which distills at between 180and 260 C. and which contains the high boiling form of vitamin D,saponifying this fraction, dissolving the non-saponifiable portion in asolvent for the vitamin contained therein, which solvent has a lowervapor pressure than the vitamin, subjecting this mixture to high vacuumshort path distillation and separating the vita.

min in a iraction substantially free of the solvent. 6. The processwhich comprises in combination subjecting a vitamin containing marineanimal oil to high vacuum distillation, separating a irac- I 5 tionwhich contains the high boiling forms 0! vitamlns A and D, saponiiyingthis fraction, add-

